Herbicide compositions comprising imidazolinone acid, methods of preparation, and methods of use

ABSTRACT

Described are herbicide compositions (including suspension concentrates, herbicide compositions prepared therefrom), and others that include imidazolinone acid, which can optionally and preferably also include an acidifying agent, and methods of making and using such compositions.

[0001] This application claims the benefit of and is a continuation ofpatent application Ser. No. 10/103,519, filed Mar. 21, 2002, whichclaims the benefit of U.S. Provisional Application Serial No.60/325,289, U.S. Provisional Application Serial No. 60/325,342, and U.S.Provisional Application Serial No. 60/325,343, all filed Sep. 26, 2001,and the benefit of U.S. Provisional Application Serial No. 60/361,016,filed Feb. 28, 2002.

FIELD OF THE INVENTION

[0002] The invention relates to herbicide compositions comprisingimidazolinone acid, including but not limited to suspensionconcentrates, methods of preparing such herbicide compositions, andmethods of using each.

BACKGROUND

[0003] Commercially available herbicide compositions include a verylarge variety of active herbicide compounds. Such herbicide compositionscan be prepared from different types of precursor compositions, and canbe commercially available and used in a variety of different types ofcompositions, including, for example, compositions referred to aswettable powders, water dispersible granules, granules, aqueoussolutions, water soluble powders, emulsifiable concentrates, oil-basedflowables, concentrated emulsions, suspo-emulsions, emulsions,suspensions, suspension concentrates, mixtures, dispersions, andmicroemulsions, as well as others. Any of these different types ofcompositions may have different advantages or disadvantages relating tofactors such as the mode of application and the type of activeingredient included in the herbicide composition.

[0004] Examples of useful suspension concentrates are described in U.S.Pat. Nos. 6,207,617 B1 (Gillespie), U.S. Pat. No. 5,707,928 (Baker), andU.S. Pat. No. 5,268,352 (Dexter). Other exemplary suspensionconcentrates are described in Assignee's copending United States PatentApplication “Herbicide Compositions Comprising Suspension Concentratewith Glyphosate Acid, Methods of Preparation, and Methods of Use,”(Attorney's Docket Number UAP0007/US), having Ser. No. 60/325,343, filedon Sep. 26, 2001.

[0005] Examples of just a few available active herbicide compoundsinclude those of the general class known as phenoxy herbicides, e.g.,2,4-dichlorophenoxyacetic acid (known as 2,4-D), MCPA acid, MCPP acid;those of the general class known as pyridine herbicides, (e.g.,triclopyr, fluoroxypyr); those of the general class of benzoic acidherbicides, (e.g., dicamba acid); those of the general class of aryloxyphenoxy propionic acid herbicides, (e.g., fluzafop acid and quizolofopacid); water-insoluble diphenyl ether type herbicides (e.g., oxyfluorfenor acifluorfen); glyphosate compounds (N-(phosphonomethyl)glycine),e.g., in the acid form, referred to as glyphosate acid, or in a saltform such as the IPA salt form; imidazolinone herbicide compounds (e.g.,imazethapyr, imazaquin, imazapyr, imazamethabenz, imazapic, orimazamox); as well as others.

[0006] Active herbicide ingredients such as these and others can beprepared from and used in the form of solid and liquid compositionsincluding, as mentioned above, different forms of emulsions,suspensions, suspension concentrates, mixtures, dispersions,microemulsions, etc., and derivatives thereof such as diluted solutionsor solutions including other added ingredients such as additionalherbicides, surfactants, and acidifying agents.

[0007] Imidazolinones are a known active herbicide ingredient and arecommercially available, for example, under the trade designations“ARSENAL”, “CHOPPER”, “STALKER” (imazapyr); “SCEPTER”; “IMAGE”(imazaquin); “ASSERT” (imazamethabenz); “CADRE”, “PLATEAU” (imazapic);“PURSUIT” (imazethapyr); “RAPTOR”, “ODESSEY” (imazamox).

[0008] Specifically with regard to imidazolinone herbicide compounds,this compound is understood to be available in a variety of chemicallydifferent forms including imidazolinone acid and imidazolinone salts.

[0009] Surfactants may be combined with active herbicide compounds, asmentioned above, to facilitate suspending the compound and provide asuspension concentrate. U.S. Pat. No. 6,207,617 (Gillespie) generallydescribes suspension concentrate compositions that includes a specificamount of active herbicide compound and a specific polyoxyethylenealkylether or polyoxyethylene alkenylether surfactant.

[0010] Acidifying agents may be combined with herbicide compositions toimprove performance. Such herbicide compositions are described, forexample, in U.S. Pat. No. 4,994,101 (Young), and in United States PatentApplications “Herbicide Microemulsion-Forming-Concentrates,Microemulsions, and Methods” (Attorney's Docket Number UAP0003/US/2),“Herbicide Composition Comprising Herbicide Compound in Acid Form andAcidifying Agent,” (Attorney's Docket Number UAP0006/US/2), and“Herbicide Compositions Comprising Suspension Concentrate withGlyphosate Acid, Methods of Preparation, and Methods of Use,”(Attorney's Docket Number UAP0007/US/2), having Ser. Nos. 10/103,455,10/102,799, and 10/103,493, all filed on Mar. 21, 2002.

[0011] Always desirable are new forms of useful and effective herbicidecompositions. Particularly desirable can be compositions that haveimproved efficacy or that can be produced more conveniently orefficiently, or without using organic solvents.

SUMMARY OF THE INVENTION

[0012] The invention relates to herbicide compositions that includeactive herbicide compound comprising an imidazolinone in acid form. Theuse of imidazolinone in its acid form provides efficiency because theacid form does not need to be converted to the imidazolinone salt formduring processing or prior to application, as is often done withimidazolinone herbicide compounds, because the salt forms are moresoluble in water. Instead, herbicide compositions that containimidazolinone acid in the imidazolinone acid form, such as preferredsuspension concentrates, can be simple and economical to produce, andcan be efficiently distributed, prepared, and applied without takingsteps to convert the imidazolinone herbicide out of its acid form.Additionally the neutral, acid form of the compound has better uptake bya target plant, and can be less susceptible to deactivation by hardwater.

[0013] In one embodiment, herbicide compositions of the invention mayinclude a suspension concentrate that includes an active imidazolinoneacid herbicide compound, or derivatives of those suspensionconcentrates. The suspension concentrates can be used in theirsuspension concentrate form to control plant growth, or can be used toprepare derivative herbicide compositions for application to controlplant growth. For example, the suspension concentrate can be diluted orcombined with an aqueous acidifying agent, e.g., in a tank mix procedureor otherwise, to form a herbicide application composition, and canoptionally be further combined with other ingredients such as anadditional, different active herbicide compound.

[0014] Generally, it is desirable to produce herbicide compositions,including precursor compositions, easily and efficiently. Suspensionconcentrates have been found to be easily and efficiently produciblewith the use of one or more ingredients such as surfactants,dispersants, thickeners, etc., one or more of which, optionally incombination with one or more of mixing, agitation, and milling, etc.,can allow imidazolinone acid particles to be suspended and/or dispersedin water to form a suspension concentrate. Preferred surfactants mayinclude nonionic surfactant, anionic surfactant, cationic surfactant,and mixtures thereof. Preferred nonionic surfactant may include shortchain alcohol ethoxylate surfactant. Preferred anionic surfactant mayinclude sodium butyl naphthalene sulfonate, sodium di-n-butylnaphthalene sulfonate, sodium diisopropyl naphthalene sulfonate, sodiumdimethyl naphthalene sulfonate, ethoxylated tristyrylphenol phosphatepotassium salt, and mixtures thereof. Preferred cationic surfactant mayinclude ethoxylated tallow amine.

[0015] Preferred suspension concentrate herbicide compositions of theinvention can have benefits when compared to other forms of herbicideformulations, such as the absence of dust; reduction of toxicity orflammability, etc.; they can be prepared to contain essentially noorganic solvent; they can exhibit increased efficacy, for example due tolower particle size; they benefit from a low packing volume as comparedto other forms of herbicides such as powders; and the suspensionconcentrates are relatively easy to handle.

[0016] The invention also contemplates the independent general conceptof using imidazolinone acid-containing herbicide compositions generally,in combination with an acidifying agent, especially certain types ofacidifying agents, and especially to produce certain ranges of pH in aherbicide composition. Such herbicide compositions may be prepared fromor comprise different types of herbicide or herbicide precursorcompositions that are capable of containing an imidazolinone acid, forexample, compositions such as wettable powders, water dispersiblegranules, granules, aqueous solutions, water soluble powders,emulsifiable concentrates, oil-based flowables, concentrated emulsions,suspo-emulsions, emulsions, suspensions, suspension concentrates,mixtures, dispersions, and microemulsions, as well as others. Thisaspect of the invention can advantageously provide improved efficacy ofimidazolinone acid herbicide compounds. In one embodiment of theinvention, a herbicide composition can comprise an imidazolinone acidactive herbicide compound combined with acidifying agent, preferably toproduce a herbicide composition having a pH below the pKa of theimidazolinone acid. Preferred herbicide application compositions canhave a pH below about 7, or otherwise below the pKa of imidazolinoneacid compound.

[0017] In one aspect, the invention relates to a herbicide compositionthat includes a suspension concentrate that includes an imidazolinoneacid, and an acidifying agent other than sulfuric acid, in an amount sothe pH of the composition is below the pKa of the imidazolinone acid.

[0018] Another aspect of the invention relates to a herbicidecomposition that includes an imidazolinone acid and an acidifying agentother than sulfuric acid, in an amount so the pH of the composition isbelow the pKa of the imidazolinone acid. Preferred herbicidecompositions can comprise or be prepared from suspension concentrates.

[0019] Another aspect of the invention relates to a suspensionconcentrate, preferably an aqueous suspension concentrate, that includesan imidazolinone acid and a short chain alcohol ethoxylate nonionicsurfactant.

[0020] Another aspect of the invention relates to a suspensionconcentrate, preferably an aqueous suspension concentrate, that includesan imidazolinone acid and anionic surfactant.

[0021] Another aspect of the invention relates to a suspensionconcentrate that includes imidazolinone acid and surfactant, and fromgreater than 30 parts by weight imidazolinone acid to about 50 parts byweight imidazolinone acid, per 1 part by weight surfactant.

[0022] Another aspect of the invention relates to a herbicidecomposition comprising:

[0023] aqueous suspension concentrate comprising

[0024] about 25 to about 45 weight percent imidazolinone acid, and

[0025] about 0.5 to about 1.5 weight percent surfactant selected fromthe group consisting of: short chain alcohol ethoxylate nonionicsurfactant, anionic surfactant, cationic surfactant, and mixturesthereof, and

[0026] about 40 to about 60 parts by weight water; and

[0027] acidifying agent selected from the group consisting of sulfuricacid, hydrochloric acid, nitric acid, acetic acid, phosphoric acid,perchloric acid, and polyphosphoric acid, an adduct of sulfuric acid andurea, and combinations thereof, in an amount so the pH of thecomposition is below the pKa of the imidazolinone acid.

[0028] Another aspect of the invention relates to a herbicidecomposition comprising:

[0029] aqueous suspension concentrate comprising

[0030] about 25 to about 45 weight percent imidazolinone acid, and

[0031] about 0.5 to about 1.5 weight percent surfactant selected fromthe group consisting of: nonionic surfactant, anionic surfactant,cationic surfactant, and mixtures thereof, and

[0032] about 40 to about 60 parts by weight water; and

[0033] acidifying agent selected from the group consisting ofhydrochloric acid, nitric acid, acetic acid, phosphoric acid, perchloricacid, and polyphosphoric acid, an adduct of sulfuric acid and urea, andcombinations thereof, in an amount so the pH of the composition is belowthe pKa of the imidazolinone acid.

[0034] Still another aspect of the invention relates to a method ofkilling or controlling unwanted vegetation growth, the method includingthe steps of 1) preparing a herbicide composition that includesimidazolinone acid and an amount of acidifying agent, other thansulfuric acid, to reduce the pH of the herbicide composition to a pHbelow the pKa of the imidazolinone acid, and 2) applying the herbicidecomposition to control plant growth.

[0035] Still a further aspect of the invention relates to a method ofkilling or controlling unwanted vegetation growth, the method includingthe steps of 1) preparing a herbicide composition that includes asuspension concentrate that includes an imidazolinone acid and asurfactant selected from the group consisting of a short chain alcoholethoxylate nonionic surfactant, an anionic surfactant, a cationicsurfactant, and mixtures thereof, and 2) applying the herbicidecomposition to control plant growth.

[0036] Yet another aspect of the present invention relates to a methodof preparing an aqueous suspension concentrate that includesimidazolinone acid, the method including the steps of 1) combiningimidazolinone acid particles with water, surfactant comprising: a shortchain alcohol ethoxylate nonionic surfactant, anionic surfactant,cationic surfactant, and mixtures thereof, 2) mixing or agitating thewater, imidazolinone acid particles, and surfactant, and 3) wet millingthe water, imidazolinone particles and surfactant to produce asuspension concentrate.

[0037] Yet another aspect of the invention relates to a method ofpreparing herbicide composition that includes imidazolinone acid, themethod including the steps of 1) combining imidazolinone acid particleswith water and surfactant, 2) mixing or agitating the water,imidazolinone acid particles, and surfactant, 3) wet milling water theimidazolinone acid particles and surfactant, to produce a suspensionconcentrate, and 4) combining the aqueous suspension concentrate withacidifying agent in an amount to produce a herbicide composition havinga pH below the pKa of the imidazolinone acid.

DETAILED DESCRIPTION

[0038] Imidazolinone Acids

[0039] Imidazolinone compounds, and chemical derivatives thereof, are aknown type of active herbicide compound. Imidazolinone compounds are aclass of highly potent, environmentally benign, crop selectiveherbicides. The imidazolinone class of herbicides are highly desirablefor the selective control of a wide variety of grass and broadleaf weedsin the presence of agricultural crops, and in non-crop areas such asturf forestry. Imidazolinone is generally available in either the acidor salt form. The salt forms are considered to be generally soluble inwater, whereas the acid forms are considered to be generally insolublein water.

[0040] The present invention relates to herbicide compositions thatinclude imidazolinone in the acid form.

[0041] The term “herbicide composition” refers to compositions thatinclude a herbicide compound, specifically here, imidazolinone acid.Herbicide compositions of the invention can include different types ofprecursor compositions, for example, compositions referred to aswettable powders, water dispersible granules, granules, aqueoussolutions, water soluble powders, emulsifiable concentrates, oil-basedflowables, concentrated emulsions, suspo-emulsions, emulsions,suspensions, suspension concentrates, mixtures, dispersions, andmicroemulsions, as well as others. In one important embodiment,herbicide compositions of the invention may include a suspensionconcentrate that includes the active herbicide compound imidazolinone,in the acid form.

[0042] Imidazolinone in the acid form is considered to be generally aninsoluble active herbicide compound. This means, for example, dependingon temperature and pH, that imidazolinone acid can be soluble in wateror acidic water only up to a few weight percent, meaning thatapproximately 100 grams of an aqueous solution can dissolve onlyapproximately a couple of grams of imidazolinone acid, e.g.,approximately 1 gram, or one weight percent.

[0043] Examples of imidazolinone acids include imazethapyr acid,imazaquin acid, imazapyr acid, imazamethabenz acid, imazapic acid,imazamox acid, and combinations thereof. Imazethapyr acid has themolecular formula C₁₅H₁₉N₃O₄ and is commercially available generally inthe form of a powdered solid, under the trade designation “PURSUIT.”Imazaquin acid has the molecular formula C₁₇H₁₇N₃O₃ and is commerciallyavailable generally in the form of a powdered solid, under the tradedesignation “SCEPTER” and “IMAGE.” Imazapyr acid has the molecularformula C₁₃H₁₅N₃O₃ and is commercially available generally in the formof a powdered solid, under the trade designation “ARSENAL,” “CHOPPER,”and “STALKER.” Imazamethabenz acid has the molecular formula C₁₅H₁₈N₂O₃and is commercially available generally in the form of a powdered solid,under the trade designation “ASSERT.” Imazapic acid has the molecularformula C₁₄H₁₇N₃O₃ and is commercially available generally in the formof a powdered solid, under the trade designation “CADRE” and “PLATEAU.”Imazamox acid has the molecular formula C₁₅H₁₉N₃O₄ and is commerciallyavailable generally in the form of a powdered solid, under the tradedesignation “RAPTOR” and “ODESSEY.”

[0044] The pKa of each of these is understood to refer to the negativelogarithm (base 10) of the equilibrium constant K for the reaction ofthe herbicide compound between its acid form and its neutral form.Methods of determining pKa for a herbicide compound will be readilyunderstood by the skilled artisan. Exemplary imidazolinone acidsdescribed herein can generally have a pKa below about 7, especiallybelow about 5 or 4, for example, the pKa of imazamethbenz isapproximately 2.9, the pKa of imazapyr is approximately 2 or 3, the pKaof imazaquin is approximately 3.8, and the pKa of imazethapyr isapproximately 3.9.

[0045] The use of imidazolinone acids can be advantageous because theacid form does not need to be converted to the imidazolinone salt formduring processing or prior to application, as is often done withimidazolinone herbicide compounds, because the salt forms are moresoluble in water. Instead, herbicide compositions that containimidazolinone acid in the imidazolinone acid form, such as preferredsuspension concentrates, can be simple and economical to produce, andcan be efficiently distributed, prepared, and applied without takingsteps to convert the imidazolinone herbicide out of its acid form. Inaddition, the acid form of imidazolinone compounds, due to its unchargedstate, can be advantageously less affected or unaffected by hard water,e.g., less susceptible to de-activation by hard water.

[0046] Suspension Concentrates

[0047] In one preferred embodiment of the invention, a herbicidecomposition includes a suspension concentrate comprising imidazolinoneacid. The term “suspension concentrate” as used herein, means acomposition also sometimes referred to as an “aqueous flowable” or a“water-based flowable” composition, which compositions are known in theherbicide art and include or consist of particles of a generallyinsoluble solid active herbicide compound in suspension (preferablyconcentrated suspension) in water. Exemplary suspension concentratesthat contain a different active herbicide, glyphosate acid, aredescribed in Assignee's copending United States Patent Application“Herbicide Compositions Comprising Suspension Concentrate withGlyphosate Acid, Methods of Preparation, and Methods of Use,”(Attorney's Docket Number UAP0007/US/2), having Ser. No. 10/103,493,filed on Mar. 21, 2002.

[0048] The suspension concentrates described herein can be produced withparticles of imidazolinone acid compounds by suspending and preferablydispersing the particles in water with the assistance of otheringredients such as surfactant (also referred to as “wetting agents”),dispersant, and other optional ingredients.

[0049] The imidazolinone acid should be in the form of particles thatexhibit physical characteristics such as size, shape, surface features,etc., that will allow the imidazolinone acid particles to be suspendedin the form of a suspension concentrate, preferably an aqueoussuspension concentrate. The particle size range can vary depending onfactors such as the other ingredients used to prepare the suspensionconcentrate and their respective amounts, but exemplary particles may bein the size range below about 10 microns, for example in the range fromabout 4 to about 8 micrometers in diameter or from about 5 to about 7micrometers in diameter.

[0050] Herbicide compositions of the invention include imidazolinoneacid in a useful amount. Useful amounts of imidazolinone acid in anyparticular composition can depend on the intended application (includingthe plant to be controlled or the crop to be protected), the mode ofapplication (e.g., field or aerial spraying or application from ahand-held spray applicator, or other technique), the method of anypreparation of a herbicide application composition, the amounts andidentities of other ingredients added to the herbicide composition, etc.For example, an amount that, in combination with one or more otheringredients described herein (e.g., such as surfactant and/ordispersant) will allow suspension and preferably dispersion of theimidazolinone acid particles to provide a suspension concentrate. In oneembodiment, useful amounts of imidazolinone acid compound in asuspension concentrate may be, for example, in the range from about 20to about 60 weight percent imidazolinone acid based on the total weightof the suspension concentrate. In another embodiment, useful amounts ofimidazolinone acid compound in a suspension concentrate may be, forexample, in the range from about 25 to about 45 weight percentimidazolinone and based on the total weight of the suspensionconcentrate. Exemplary concentrations of suspension concentratesprepared according to the invention can include 3 pounds ofimidazolinone acid per gallon, and 4 pounds of imidazolinone acid pergallon. Other concentrations of imidazolinone acid will also be useful.

[0051] Other ingredients may be used to prepare useful suspensionconcentrates and herbicide compositions. Exemplary other ingredientsinclude surfactant, dispersant, thickener, and antifoaming agent.

[0052] As used in the present invention, surfactant can be used forseveral purposes. In one embodiment, surfactant is used to at leastfacilitate suspending the imidazolinone acid particles in a suspensionconcentrate by helping to wet and/or disperse the solid particles.Surfactants can lower the surface tension of the water, helping toreplace air on the surface of particles of the imidazolinone acid withwater, thereby suspending the particles. If milling is required (seebelow), during milling, new particle surfaces are created by mechanicalbreakdown of solid imidazolinone particles and surfactant adsorbs ontothe particle surfaces to give rise to fluidity of the suspension.

[0053] A very large variety of surfactants are known and commerciallyavailable, including such different classes as anionic surfactants,nonionic surfactants, cationic surfactants, ionic surfactants, andamphoteric surfactants, etc. According to the invention, the surfactantcan be any surfactant or combination of surfactants (e.g., blends ofanionic, nonionic or cationic surfactants), useful to produce thesuspension concentrate.

[0054] According to the invention, dispersant can also be used tofacilitate preparation of a suspension concentrate containingimidazolinone acid particles. A dispersant can stabilize and maintain aseparation between suspended particles, which otherwise may have atendency to flocculate due to attractive forces. Dispersants can providerepulsive forces to balance the tendency to flocculate. Usefuldispersants include anionic and nonionic dispersants. An example of auseful, commercially available nonionic dispersant is Tersperse 4892from Huntsman.

[0055] Examples of useful surfactants and dispersants are listed in thetable below. GENERAL TRADE NAME COMMON NAME FUNCTION CLASSIFICATIONTomadol 1-5 11 carbon 5 mole linear alcohol wetting agent nonionicSurfonic L12-6 12 carbon 6 mole linear alcohol wetting agent nonionicTrymeen 6607 20 mole tallow amine wetting agent/adjuvant cationicStepfac 8170 phosphate ester dispersant/adjuvant anionic Surfonic PE1218 phosphate ester dispersant/adjuvant anionic Surfonic OP-70  7 moleoctylphenol wetting agent/adjuvant nonionic Tergitol NP-9  9 molenonylphenol wetting agent/adjuvant nonionic Soprophor 796P tristerolphenol EO/PO dispersant nonionic Soprophor FLK tristerolphenol potassiumphosphate dispersant anionic Polyfon H sodium lignosulfonate dispersantanionic Morwet D425 napthalene formaldehyde condensant dispersantanionic Morwet IP naphthalene sulfonates wetting agent anionic PluronicL1061 block copolymer dispersant nonionic Tersperse 4984 blockcopolymer/alcohol ethoxylate dispersant, wetting nonionic Tersperse 2500surfactant dispersant anionic Surfonic DOS60 sulfosuccinate wettingagent anionic LI-700 lecithin derivative adjuvant nonionic Goodrite K732polyacrylic acid dispersant anionic

[0056] An anionic surfactant is a surface-active molecule in which anactive portion of a lipophilic portion of the molecule forms a negativeion (i.e., anion) when placed in aqueous solution. Exemplary anionicsurfactants include phosphoric acid ester surfactants (sometimesreferred to as “phosphate ester” surfactants), sodium alkyl naphthalenesulfonate surfactants, and ethoxylated tristyrylphenol phosphate salts.

[0057] Exemplary sodium alkyl naphthalene sulfonate surfactants includesodium butyl naphthalene sulfonate, sodium di-n-butyl naphthalenesulfonate, sodium diisopropyl naphthalene sulfonate, sodium dimethylnaphthalene sulfonate, and mixtures thereof. Sodium butyl naphthalenesulfonate is commercially available, for example, under the trade name“MORWET B” from Witco/Crompton, Greenwich, Conn. Sodium di-n-butylnaphthalene sulfonate is commercially available, for example, under thetrade name “MORWET DB” from Witco/Crompton, Greenwich, Conn. Sodiumdiisopropyl naphthalene sulfonate is commercially available, forexample, under the trade name “MORWET IP” from Witco/Crompton,Greenwich, Conn. Sodium dimethyl naphthalene sulfonate surfactant iscommercially available, for example, under the trade name “SELLOGEN HR”from Henkle Corp., Cincinnati, Ohio.

[0058] An exemplary ethoxylated tristyrylphenol phosphate potassium saltsurfactant is commercially available, for example, under the trade name“SOPROPHOR FLK” from Rhodia, Cranbury, N.J.

[0059] A nonionic surfactant is a surface-active molecule that does notcontain ionizable polar end groups but does contain hydrophilic andlipophilic portions. Exemplary nonionic surfactants includepolyoxyethylene alkylether or alkenylether surfactants. Nonionicsurfactant used to prepare a suspension concentrate as described hereinmay include long or short chain alcohol ethoxylate surfactant. Thealcohol ethoxylate surfactant may be branched or linear.

[0060] An example of a useful nonionic polyoxyalkylene surfactantincludes alcohol ethoxylate having the general formula:

R—O—(CH₂)_(x)O)_(y)—H

[0061] wherein R may be “long” or “short” chain and “branched” or“linear” alkyl. R preferably can be a “short chain” branched or linearalcohol, meaning that it can have from about 3 to 23 or fewer carbonatoms. With respect to the oxyalkylene, x can preferably be in the rangefrom about 2 to 5, preferably from about 2 to 4 (e.g., 2 or 3, for apolyoxyethylene or polyoxypropylene, respectively) and y can preferablybe in the in the range from 5 to 25.

[0062] Examples of useful short chain nonionic polyoxyalkylenes includelinear alcohol polyoxyethylenes having the general formula:

CH₃(C₂H₄)_(m)O(C₂H₄O)_(n)H

[0063] wherein CH₃(C₂H₄)_(m) is a short chain linear alkyl having fromabout 3 to 23 or fewer carbon atoms (i.e., m can be in the range fromabout 1 to 11 carbon atoms), and n is in the range from about 5 to 25.

[0064] Another example is short chain nonionic polyoxypropylenes havingthe general formula:

CH₃(C₂H₄)_(m)O(C₃H₆O)_(n)H,

[0065] wherein CH₃(C₂H₄)_(m) is a short chain linear alkyl having fromabout 3 to 23 or fewer carbon atoms (i.e., m can be in the range fromabout 1 to 11 carbon atoms), and n can preferably be in the range fromabout 5 to 25.

[0066] Exemplary short chain linear alcohol ethoxylate surfactant arecommercially available, for example, under the trade names “SURFONICL12-6” from Huntsman, Austin, Tex., “SURFONIC L24-7” from Huntsman,Austin, Tex., “TERGITOL 15-S-7”, “TERGITOL 24-L-60”, “ALPHONIC 1012-60”,“ALPOHONIC 1414-60”, “BIOSOFT ET 630,” from Stepan Company, Chicago,Ill., and “GENOPAL 24-L-60.”

[0067] Other exemplary surfactants include polyethylene glycol, fattyacid ethoxylates, phosphate esters, octyl phenol ethoxylates, and nonylphenol ethoxylates.

[0068] Useful polyethylene glycol surfactants are commerciallyavailable, for example, under the trade names “ADEKA PEG” from AsahiDenka Kogyo, Tokyo, Japan.

[0069] Useful fatty acid ethoxylate surfactants are commerciallyavailable, for example, under the trade names “NINEX MT-610”, “NINEXMT-615”, and “NINEX MT-630” from Stepan, Northfield, Ill.

[0070] Useful phosphate ester surfactants are commercially available,for example, under the trade names “STEPFAC 8180”, “STEPFAC 8181”, and“STEPFAC 8182” from Stepan.

[0071] Useful octyl phenol ethoxylate surfactants are commerciallyavailable, for example, under the trade name “MAKON OP-9” from Stepan,Northfield, Ill.

[0072] Useful nonyl phenol ethoxylate surfactants are commerciallyavailable, for example, under the trade names “MAKON 4”, “MAKON 6”,“MAKON 8”, “MAKON 10”, “MAKON 12”, and “MAKON 14” from Stepan,Northfield, Ill.

[0073] A cationic surfactant is a surface-active molecule in which anactive portion of a lipophilic portion of the molecule forms a positiveion (i.e., cation) when placed in aqueous solution. In one embodiment,exemplary cationic surfactant includes ethoxylated tallow amine.

[0074] Suspension concentrates of the invention include surfactant in auseful amount. Useful amounts of surfactant (“surfactant” refers to oneor a combination of surfactants) can be any useful amount, such as anamount that, in combination with one or more other ingredients describedherein (e.g., such as dispersant) will allow preparation of a usefulherbicide composition. Useful amounts of surfactant will be apparent tothe skilled artisan based on this overall description. For example,useful amounts of surfactant can depend on the intended application(including the plant to be controlled or the crop to be protected), themode of application (e.g., field or aerial spraying or application froma hand-held spray applicator, or other technique), the method of anypreparation of a herbicide application composition, the amounts andidentities of other ingredients added to the herbicide composition, etc.For example, an amount that, in combination with one or more otheringredients described herein (e.g., imidazolinone acid, dispersant,thickener) will allow suspension and preferably dispersion of theimidazolinone acid particles to provide a suspension concentrate. Usefulamounts of surfactant in a suspension concentrate may be in the rangefrom about 0.5 to about 1.5 weight percent surfactant based on the totalweight of the suspension concentrate. Stated differently, useful amountsof imidazolinone acid and surfactant in a suspension concentrate may be,for example, from greater than 30 parts by weight imidazolinone acid toabout 50 parts by weight imidazolinone acid, per 1 part by weightsurfactant, e.g., from 31 to 45 parts by weight imidazolinone acid per 1part by weight surfactant. In a particular embodiment, useful amounts ofimidazolinone acid and short chain alcohol ethoxylate nonionicsurfactant in a suspension concentrate may be, for example, from greaterthan 30 to about 50 parts by weight imidazolinone, per 1 part by weightshort chain alcohol ethoxylate nonionic surfactant.

[0075] The amount of dispersant used in a suspension concentrate can beany useful amount that will allow the preparation of a herbicidecomposition. In one embodiment, a useful amount of dispersant can be anamount that will allow the preparation of a suspension concentrate, andthat may help to stabilize a suspension concentrate, e.g., by preventingflocculation. Useful amounts may depend on the type of dispersant andthe composition of the herbicide composition, and will be apparent tothe skilled artisan. In one embodiment, useful amounts of dispersant ina suspension concentrate may be, for example, in the range from about 2to about 5 weight percent dispersant based on the total weight of thesuspension concentrate.

[0076] Dispersant may be combined with other ingredients (e.g., anionic,nonionic, or cationic surfactants) to allow preparation of a usefulsuspension concentrate, such as by aiding the stabilization of asuspension concentrate, e.g., by preventing flocculation. Usefulcombinations of dispersant and other ingredients may depend on the typeof dispersant and other ingredient (e.g., anionic dispersant, nonionicdispersant, anionic surfactant, nonionic surfactant), and thecomposition of the, for example, suspension concentrate, and will beapparent to the skilled artisan. In one embodiment, a useful combinationof dispersant and other ingredients in a suspension concentrate includeanionic dispersant and anionic surfactant. In another embodiment, auseful combination of dispersant and other ingredients in a suspensionconcentrate include anionic dispersant and nonionic surfactant. Inanother embodiment, a useful combination of dispersant and otheringredients in a suspension concentrate include nonionic dispersant andanionic surfactant. In still another embodiment, a useful combination ofdispersant and other ingredients in a suspension concentrate includenonionic dispersant and nonionic surfactant.

[0077] Other ingredients, additives, active herbicide compounds, oradjuvants can also be included in a suspension concentrate according tothe invention, as will be appreciated by those skilled in the relevantarts. For example, an antifreeze may be useful, such as propylene glycolor other low molecular weight alcohols or polyols, in an amount toreduce the freezing point of a suspension concentrate. The amount of theantifreeze can be any amount that is useful, as will be understood bythe skilled artisan. Exemplary amounts of antifreeze in a herbicidecomposition (e.g., suspension concentrate) can be below about 20 weightpercent based on the total weight of the suspension concentrate, forexample from 1 to about 15 weight percent, or from about 5 to about 10weight percent.

[0078] Thickeners can be included in the suspension concentrate toprovide gravitational stabilization by increasing viscosity. Usefulthickeners include chemical compounds and polymeric materials that willbe known to and understood by the skilled artisan, and include,generally, natural and synthetic starches, gums, and other types ofchemical compounds that will increase the viscosity of a solution.Thickening agents are well known in the chemical and polymer arts, andinclude, inter alia, polyacrylamides, cellulosic resins andfunctionalized cellulosic resins, polyacrylic acids, polyethyleneoxides, and the like. Commercially available examples include Kelzan andRhodaopl 23 xanthan gums, Attagel 50 and Attaflow FL clays, Carbopol 910polyacrylic acid polymer, Kelcosol sodium alginate, and Bentolitepurified Bentonite.

[0079] A useful amount of thickener will result in increased viscosityand stability, without causing viscosity build that would be excessivefor application of the composition as a herbicide. Exemplary amounts ofthicker in a herbicide composition (e.g., suspension concentrate) can bebelow about 5 or 10 weight percent, based on the total weight of thesuspension concentrate, may generally be useful. Preferred amounts maybe less 0.5 weight percent for gums or cellulose resins.

[0080] Another additional ingredient that can be used in the suspensionconcentrate may include an antifoaming agent. Antifoaming agents arewell understood in the chemical and herbicide arts, and a variety ofuseful examples are commercially available. Antifoam agents aresubstances such as silicones, organic phosphates, and alcohols thatinhibit the formation of bubbles in a liquid by reducing surfacetension. One specific example of a commercially available antifoam agentis SAG 10 (a 10% silicone in water), from Witco OSI. The amount ofantifoaming agent used in a suspension concentrate will also be apparentto the skilled artisan, with typical amounts being less than 1 percentby weight, e.g., less than 0.5 percent by weight.

[0081] Additional active herbicide compounds can also be included in thesuspension concentrate. Preferably, additional active herbicidecompounds can be compounds present in an acid form, such as any one ormore acid form herbicides described, e.g., in Applicants' copending U.S.patent applications “Herbicide Microemulsion-Forming-Concentrates,Microemulsions, and Methods” (Attorney's Docket Number UAP0003/US/2);“Herbicide Composition Comprising Herbicide Compound in Acid Form andAcidifying Agent,” (Attorney's Docket Number UAP0006/US/2); and“Herbicide Compositions Comprising Suspension Concentrate withGlyphosate Acid, Methods of Preparation, and Methods of Use,”(Attorney's Docket Number UAP0007/US/2), having Ser. Nos. 10/103,455,10/102,799, and 10/103,493, filed Mar. 21, 2002, specifically includingglyphosate acid active herbicide as well as all other acid herbicidecompounds listed therein, or still other herbicides capable of existingin an acid form.

[0082] Other useful additives or adjuvants that can be used in asuspension concentrate according to the present invention may includeother surfactants, antimicrobial agents, anticorrosion agents, acids oracidifying agents, and other ingredients. Surfactants having functionsof wetting, spreading, or penetrating, preferably to improve efficacy ofa herbicide composition, may also be added or can be added when a tankmix is made for application. Organic solvents may be included in aherbicide composition (e.g., suspension concentrate) if desired, but aregenerally not used or needed.

[0083] Suspension concentrates of the invention may include water in anyuseful amount. For example, a useful amount of water can be an amountthat in combination with one or more other ingredients described herein(e.g., such as surfactant and/or dispersant) will provide a suspensionconcentrate by allowing suspension and preferably dispersion of theimidazolinone acid particles. Relative amounts of water and the otheringredients used to prepare a suspension concentrate can be any amountsthat produce a useful herbicide composition in the form of a suspensionconcentrate. Relative amounts of different ingredients (imidazolinoneacid, surfactant, etc.) in any particular composition can depend on theintended application (including the plant to be controlled or the cropto be protected), the mode of application (e.g., field or aerialspraying or application from a hand-held spray applicator, or othertechnique), the method of any preparation from a suspension concentrateto a herbicide application composition, the amounts and identities ofother ingredients added to a herbicide composition (e.g., suspensionconcentrate), etc. In one embodiment, a useful amount of water within asuspension concentrate can be from about 40 to about 60 parts by weightwater, preferably from about 40 to 55 parts by weight water. The amountof water for any suspension concentrate will relate to theconcentration; a 3 pound per gallon suspension concentrate may have alower amount of water per pound than a 4 pound per gallon suspensionconcentrate.

[0084] Suspension concentrate according to the invention may or may notinclude organic solvent. Preferred suspension concentrates are aqueous,meaning they contain essentially no organic solvent. “Essentially noorganic solvent” as used in the present invention means a small amountof organic solvent relative to the amount of other ingredients, forexample, less than 5 percent by weight, preferably less than 2 percentby weight, more preferably less than 1 percent by weight, and even morepreferably less than 0.5 percent by weight.

[0085] Still other ingredients can also be added to a suspensionconcentrate of the invention to produce a derivative herbicidecomposition or herbicide application composition. These addedingredients may be useful in the herbicide composition for purposes ofdilution, stability, pH adjustment, anti-foaming, or to otherwisefacilitate application or increase efficacy. These other ingredients maybe added to the suspension concentrate or derivative herbicidecomposition at any time and in any order, as desired or convenient.Exemplary additional ingredients include water, antifoaming agents,acidifying agents, anticorrosion agents, etc.

[0086] Herbicide Compositions Comprising Acidifying Agent

[0087] According to a broad concept of the invention, a herbicidecomposition comprising an imidazolinone acid can be used in combinationwith an acidifying agent. The herbicide composition can comprise or beprepare from any of a variety of forms of herbicide compositions, aswill be found to be useful, such as but not limited to a suspensionconcentrate. Such herbicide compositions may be able to be prepared fromor comprise any form of herbicide composition capable of containing animidazolinone in its acid form, such as from among compositions referredto as wettable powders, water dispersible granules, granules, aqueoussolutions, water soluble powders, emulsifiable concentrates, oil-basedflowables, concentrated emulsions, suspo-emulsions, emulsions,suspensions, suspension concentrates, mixtures, dispersions, andmicroemulsions, or others, as may be useful. Thus, the inventioncontemplates generally the use of herbicide compositions containingimidazolinone acid as an active herbicide compound, in combination withacidifying agent, to improve efficacy.

[0088] While wishing not to be bound by theory, it is believed that thedirect application of the acid form of an imidazolinone, especially aspart of a herbicide composition having a pH below the pKa of theimidazolinone acid compound, can effect improvements in plant control byone or both of the following mechanisms. First, a neutral (acid)molecule can have an easier time penetrating a cuticle on a plant,compared to a charged (salt) molecule. Secondly, an acidifying agent anda low pH of a herbicide composition can have a damaging effect on aplant's surface, thereby letting more herbicide penetrate the surface.Also, the neutral acid molecule can be less susceptible to de-activationby hard water.

[0089] Particularly preferred herbicide compositions can be formulatedto include an acidifying agent in an amount sufficient to reduce the pHof the herbicide composition to below the pH of the imidazolinone acid,e.g., to a pH below about 7, preferably below about 5 or about 4.Preferably, the pH of the herbicide composition is below the pKa of therelevant imidazolinone acid. E.g., depending on the particularimidazolinone and its pKa, a pH of below about 4, 3.9, 3.8, 3.0, 2.9, or2.0, may be preferred.

[0090] A variety of different acidifying agents can be useful incombination with different forms of imidazolinone-containing herbicidecomposition. The particular acidifying agent chosen and the amount usedcan be based on factors including the intended use or application of theherbicide composition (including the identity of the target undesirableplant growth and any nearby desirable plant growth) the method ofapplication, physical and chemical properties of the herbicideapplication composition, and others. The acidifying agent may be any ofa variety of suitable organic or inorganic acids, of any useful strengthor concentration, that can be added to a herbicide composition,preferably without causing substantial or undue negative effects such asreaction with an ingredient of the herbicide composition such as theimidazolinone acid, precipitation, etc. It will be understood that anacidifying agent can be in a concentrated or diluted form, as necessaryor desirable.

[0091] Examples of a certain type of acidifying agent are described inU.S. Pat. Nos. 4,445,925, 4,994,101, 5,288,692, (Young) the disclosuresof which are incorporated herein by reference. Other exemplaryacidifying agents are known, and still others are described inAssignee's copending United States Patent Application entitled“Herbicide Composition Comprising Herbicide Compound in Acid Form andAcidifying Agent,” (Attorney's Docket Number UAP0006/US/2) having Ser.No. 10/102,799 filed on Mar. 21, 2002, and incorporated herein byreference. See also Assignee's copending United States PatentApplications entitled “Herbicide Compositions Comprising SuspensionConcentrate with Glyphosate Acid, Methods of Preparation, and Methods ofUse,” (Attorney's Docket Number UAP0007/US/2), and “HerbicideMicroemulsion-Forming-Concentrates, Microemulsions, and Methods,”(Attorney's Docket Number UAP0003/US/2), having Ser. Nos. 10/103,493 and10/103,455, filed on Mar. 21, 2002, and each of which is incorporatedherein by reference.

[0092] One specific example of a useful type of acidifying agentincludes adducts of sulfuric acid, and an “amide” according to theformula:

[0093] wherein X is chalcogen, and each of R₁, R₂ and R ₃ isindependently selected from hydrogen and organic radicals. As usedherein, “amide” encompasses all compounds of formula (1) regardless ofthe chalcogen. The molar ratio of amide to acid is usually in the rangeof about 1/4 to less than 2 so that at least some of the acid is presentas the monoamide-acid adduct.

[0094] When R₁, R₂, and R₃ are organic radicals, they may be cyclic oracyclic, straight or branched chained, and can contain one or moreheteroatoms such as sulfur, nitrogen, oxygen, phosphorus and the like.Further, R₁, R₂ and R₃ can contain one or more substituents such asthiol, hydroxy, nitro, amino, nitrile, amide, ester and halogen groupsand others. Such organic radicals may contain aryl groups such asaralkyl and alkaryl groups. Certain preferred organic radicals can befree of olefinic or alkynyl unsaturation and can generally have up toabout 20, preferably up to about 10 carbon atoms.

[0095] Particularly preferred amides include urea, thiourea, formamide,dimethylformamide, biuret, triuret, thioformamide, and combinations ofthese.

[0096] The chalcogens are elements of Periodic Group VI-B and includeoxygen, sulfur, selenium, tellurium, and polonium. Oxygen and sulfur canbe preferred due to low cost, availability, low toxicity, and chemicalactivity, and oxygen is the most preferred.

[0097] A specific example of an adduct according to formula (1) can bethe sulfuric acid/urea adduct:

[0098] While the sulfuric acid/urea adduct of Formula 2 is specificallyidentified to be useful according to the invention, neither of thatadduct nor sulfuric acid is specifically required to be the acidifyingagent, and either of the adduct or sulfuric acid can be optionallyincluded or entirely excluded from the methods and compositions of theinvention.

[0099] Other examples of acidifying agents include acids such assulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, aceticacid (e.g., “glacial” acidic acid), perchloric acid, polyphosphoricacid, and any other acidifying agent that can be used to affect the pHof a herbicide composition, especially to prepare a herbicidecomposition including imidazolinone acid and having a pH below the pKaof an imidazolinone compound. These and other acidifying agents can beused alone or in combination. Various such acids are commerciallyavailable in different forms and concentrations, such as solids, liquid(aqueous) solutions, concentrated liquid solutions, etc., or can beprepared by one of skill in the chemical arts. Any such form ofacidifying acid may be useful to reduce the pH of a herbicidecomposition comprising an imidazolinone acid, preferably without causingany undue negative effects. The chosen form of acidifying agent may bebased on commercial availability, safety considerations, convenience,and the overall desired properties of the herbicide composition, itsdifferent ingredients (e.g., the herbicide compound), and its desiredmethod of preparation and use.

[0100] The amount of acidifying agent added to a herbicide compositioncan be based on factors including the particular composition andchemistry of the herbicide composition, including the amounts andchemistries of ingredients such as the amount of water and the amountsand types of surfactant and herbicide compound; the form of theherbicide composition (e.g., suspension concentrate) and itsconcentration; the type of acidifying agent and its chemistry andstrength (concentration); the desired pH; etc. Preferred amounts of anyparticular acidifying agent can be capable of improving the efficacy ofthe herbicide composition as applied, and particularly preferred amountswill be sufficient to produce an application composition having a pHbelow about 7.0, preferably below about 5 or about 4 (e.g., about 3.9,3.8, 3.0, 2.9, 2.0), or otherwise below the pKa of imidazolinone acidcompound.

[0101] Useful amounts of acidifying agent used in a herbicidecomposition will be quite varied considering the above factors.Relatively strong concentrations of liquid (aqueous) acidifying agentsolutions such as 93% liquid sulfuric acid, 72% phosphoric acid, 85%polyphosphoric acid, 90% nitric acid, 99% glacial acetic acid, etc., canbe added directly or can be first diluted and then added to a herbicidecomposition in an amount to bring the pH below about 7.0, preferablybelow about 5 or about 4 (e.g., about 3.9, 3.8, 3.0, 2.9, 2.0), orotherwise below the pKa of imidazolinone acid compound. In terms ofvolume percent, very generally speaking, useful amounts of aqueousacidifying agent such as those listed above can be below about 5 or 10volume percent, e.g., for a suspension concentrate herbicidecomposition, in the range from about 0.01 to about 4 parts by volumeaqueous acidifying agent based on the total by volume of a suspensionconcentrate and acidifying agent. Volumes of acidifying agent outside ofthis range may also be useful, depending on the form and concentrationof the herbicide composition and the composition and strength of theacidifying agent, and useful amounts can be identified to achieve adesired pH of a herbicide composition.

[0102] Optionally, the herbicide composition comprising imidazolinoneacid and acidifying agent can also include additional ingredients,including additional active herbicide compound, preferably additionalactive herbicide compound that can and does exist as an acid in theherbicide composition. The additional herbicide compound can be any ofthe acid form active herbicide compounds described in Applicants'copending U.S. patent applications “HerbicideMicroemulsion-Forming-Concentrates, Microemulsions, and Methods”(Attorney's Docket Number UAP0003/US/2); “Herbicide CompositionComprising Herbicide Compound in Acid Form and Acidifying Agent,”(Attorney's Docket Number UAP0006/US/2); and “Herbicide CompositionsComprising Suspension Concentrate with Glyphosate Acid, Methods ofPreparation, and Methods of Use,” (Attorney's Docket NumberUAP0007/US/2), having Ser. Nos. 10/103,455, 10/102,799, and 10/103,943,filed on Mar. 21, 2002. These specifically include glyphosate acid,glyphose acid in a suspension concentrate, microemulsions containing anacid form of active herbicide compound, any other forms of acid activeherbicide compound, or any derivatives or combinations of these.

[0103] Methods of Making Herbicide Compositions

[0104] Certain methods of preparing herbicide compositions that containimidazolinone acids will be recognized and understood by those of skillin the herbicide arts.

[0105] One method of preparing a herbicide composition containing animidazolinone acid is to prepare a suspension concentrate (as discussedabove) comprising imidazolinone acid.

[0106] One exemplary method of producing such a suspension concentrateherbicide composition starts with imidazolinone acid particles in theform of a wet cake or dry (granular, powder) acid, generally having arelatively large particle size (e.g., greater than about 10 microns).The wet cake or dry particles of that size can be mixed or dispersedinto a liquid. This can be done, for example, by combining theimidazolinone acid particles with water and other ingredients withagitation or mixing to disperse the particles. For example, theimidazolinone acid particles can be added to water and one or more ofsurfactant, antifreeze, and antifoam, and mixed for about 20-30 minutesusing a high-speed mixer to disperse the imidazolinone acid particles.Next, dispersant may be added to the mixture and mixed for about 10minutes. The mixture of imidazolinone acid, water, and other ingredientscan be further processed toward a suspension concentrate by methods thatwill process the imidazolinone acid particles into a form that allowssuspension of the particles in the form of a suspension concentrate, forinstance by reducing the size of the particles. Thus, a processing stepcan be to reduce the size of imidazolinone acid particles to a size thatwill allow the particles, in combination with one or more of the otheringredients described herein such as surfactant and/or dispersant, to bemaintained in a stable suspension concentrate composition. An exemplarymethod of reducing the size of the imidazolinone acid particles is byusing milling techniques, e.g., what is referred to as “wet milling.” Atypical such average particle size useful for providing a suspensionconcentrate can be below about 10 micrometers in diameter, for examplein the range from about 4 to about 8 micrometers in diameter or fromabout 5 to about 7 micrometers in diameter. Any method of reducingparticle size may be useful, such as by using an attrition mill, ballmill, sand mill, or other milling process. Further in such embodiment, auseful mechanical agitation step may be performed to add additionalingredients, if desired, such as thickening agent and antimicrobialagents.

[0107] After reduction of the particle size, the solution containing thesuspended imidazolinone acid particles can be further combined with athickener, by mixing the thickener into the solution.

[0108] The suspension concentrate can preferably be stable in the formof a suspension concentrate for a useful period, meaning that thesuspension concentrate does not settle or otherwise transform out of thesuspension concentrate form, and maintains the form of a suspensionconcentrate, for a useful amount of time. Useful periods of stabilitycan depend on timing, e.g., between preparation, further processing of,and use (application) of the suspension concentrate, which time periodsmay vary greatly based on convenience, preference, inherent stability ofthe suspension, or other factors. If a suspension concentrate or aderivative form of the suspension concentrate can be applied in a shortor very short period of time after preparation, longer-term stability isnot required. Exemplary suspension concentrates of the invention can bestable at approximately room temperature and in substantiallyundisturbed and un-agitated environments for periods in excess of 6 or12 months. Longer or shorter periods would also be useful.

[0109] Thus, an exemplary method of preparing a herbicide composition(suspension concentrate) including imidazolinone acid includes 1)combining imidazolinone acid particles with water and surfactantselected from the group consisting of: nonionic surfactant, anionicsurfactant, cationic surfactant, and mixtures thereof, 2) mixing oragitating the water, imidazolinone acid particles, and surfactant, and3) wet milling the water, imidazolinone acid particles, and surfactantto produce a suspension concentrate. Preferably, the suspensionconcentrate can be an aqueous suspension concentrate.

[0110] An exemplary general method of preparing a herbicide compositionincluding a suspension concentrate comprising imidazolinone acid andfurther comprising an acidifying agent, includes: 1) combiningimidazolinone acid particles with water and surfactant, 2) mixing oragitating the water, imidazolinone acid particles, and surfactant, 3)wet milling water, imidazolinone acid particles, and surfactant toproduce a suspension concentrate, and 4) combining the suspensionconcentrate with acidifying agent other than sulfuric acid in an amountto produce a herbicide composition having a pH below the pKa of theimidazolinone acid. Preferred suspension concentrates can be aqueoussuspension concentrates.

[0111] Other types or forms of herbicide compositions that comprise animidazolinone acid will be able to be produced by methods known in theherbicide and herbicide composition arts, with the exact methoddepending in large part on the type of herbicide composition, e.g.,whether the form is includes any one of a wettable powder, waterdispersible granule, granule, aqueous solution, water soluble powder,emulsifiable concentrate, oil-based flowable, concentrated emulsion,suspo-emulsion, emulsion, suspension, mixture, dispersion,microemulsion, or another. Ingredients of such herbicide compositionscan be combined by known methods, including one or a combination ofmixing, agitating, dispersing, milling of the imidazolinone acidparticles, and may be combined with other materials such as water,solvent, acidifying agent or other herbicide compound (especially activeherbicide compounds in acid form), surfactants, dispersants, thickeners,other additives, etc. Any of the steps can be done in any order, such asmilling the imidazolinone acid particles and adding the milled particlesto other ingredients, such as water, surfactant, dispersant, thickener,solvent, etc., or by adding the particles to other ingredients, followedby wet milling. The herbicide composition comprising imidazolinone acidcan be combined with other active herbicide compounds, preferably activeherbicide compounds in acid form, in any manner.

[0112] Methods of Using

[0113] A herbicide composition as described, comprising imidazolinone inacid form, optionally in combination with an acidifying agent, includingbut not limited to a herbicide composition comprising or derived from asuspension concentrate, can be applied directly to a field or plant tocontrol undesired plant growth, or can be combined with otheringredients to form a derivative herbicide composition for application.A herbicide composition having a concentration of herbicide compound(here, an imidazolinone acid) that would normally be applied to a fieldor plant to control undesired plant growth, can be referred to herein asa “herbicide application composition.” “Herbicide applicationcomposition” refers to such a herbicide composition, as opposed, forexample, to a herbicide composition having a higher concentration ofherbicide compound, which could occur in preparation, storage, shipping,or sale of a herbicide composition.

[0114] Suspension concentrate compositions as described herein arecapable of controlling plant growth if applied directly to a plant.Similarly, other concentrated forms of herbicide compositions describedherein, e.g., comprising imidazolinone acid and an acidifying agent,optionally in combination with other active herbicide compounds,especially active acid herbicide compounds, can be useful when directlyapplied in concentrated forms. Yet it can be typical for reasons ofefficiency, cost, convenience, techniques presently used in applyingherbicide compositions, and environmental considerations, to use arelatively diluted form of herbicide composition to conveniently apply aspecific and known amount of herbicide compound per acre or per otherunit of application. By way of example, herbicide applicationcompositions can include any herbicide composition having such aspecific concentration of imidazolinone acid for application, e.g., to afield, and specifically include derivatives of suspension concentratesor derivatives of different forms of concentrated herbicidecompositions, prepared by combining a suspension concentrate or otherconcentrated herbicide composition with one or more of water, acidifyingagent, another herbicide, or other ingredients.

[0115] Herbicide compositions containing imidazolinone in acid form canbe used for immediate and long-term, post-emergent control of a largevariety of different forms of vegetation, in agricultural ornon-agricultural settings. As an example, a suspension concentrate orother concentrated herbicide composition that contains an imidazolinoneacid could be applied directly to plants for controlling plant growth,although this may include an unnecessarily potent concentration of theimidazolinone acid. Furthermore, it may as a general matter be difficultto uniformly apply a small amount of concentrated herbicide compositionto a large area without dilution. A concentrated form would instead morelikely be a product sold commercially as a herbicide concentrateproduct, which would be a composition that includes a relatively highconcentration of imidazolinone acid active herbicide compound, asmanufactured or packaged for sale, and which may typically be diluted orcombined with other ingredients prior to use to form a herbicideapplication composition.

[0116] A concentrated herbicide composition comprising imidazolinoneacid, e.g., a suspension concentrate, could be purchased by distributorsor suppliers, or directly by consumers such as farmers, any of whomcould add optional ingredients such as water, an acidifying agent (e.g.,in the form of a solid, powder, or an aqueous solution, etc.), oranother type of herbicide formulation or herbicide compound. Theadditional ingredients could, for example, be added and mixed in a tankimmediately prior to application. A concentrated herbicide compositionsuch as a suspension concentrate would typically be diluted with water.A typical dilution would be 1 pint of suspension concentrate in 15gallons of water for ground application. Another typical dilution wouldbe 1 pint of suspension concentrate in 3-5 gallons of water forapplication by air.

[0117] In one embodiment of a distribution system, a concentratedherbicide composition comprising an imidazolinone acid, e.g., asuspension concentrate, could be sold to farming product or nurserydealers, or the like, who could dilute the herbicide composition withwater and/or add other ingredients such as an acidifying agent or otheractive herbicide. This could be particularly convenient if such a dealernormally kept a stock of acidifying agent such as phosphoric acid orsulfuric acid, etc. The herbicide composition combined with acidifyingagent by the dealer could be sold to an end consumer who could use thecomposition as purchased or who could optionally further dilute thepurchased composition or add other ingredients to the purchasedcomposition such as an additional acid form herbicide compound by tankmixing.

[0118] A herbicide application composition can contain a useful amountof imidazolinone acid active herbicide compound, based on factors ofefficacy, safety, application rate, etc. Similarly, a useful amount ofherbicide application composition (containing the useful amount ofimidazolinone acid) to be applied to a plant or a field, will be readilyunderstood by those of skill, based, e.g., on desired efficacy, safety,application rate, and environmental factors, etc. The particular amountof imidazolinone acid in any specific herbicide application compositionwill depend on factors known and as described above. Advantageously,certain preferred herbicide application compositions of the invention,especially those that include an acidifying agent, and in particularthose that also have a reduced pH (below about 7.0, preferably belowabout 5 or about 4 (e.g., about 3.9, 3.8, 3.0, 2.9, 2.0), or otherwisebelow the pKa of imidazolinone acid compound), can be applied at lowerdosages or “application rates” (lower amounts of herbicide compound perplant or per acre) relative to other herbicide compositions containingother forms of imidazolinone (e.g., the salt form), or not at a reducedpH as described.

[0119] Examples of dosages (“application rates”) of imidazolinone acid,especially as included in a herbicide compositions of a describedrelatively low pH, to a field, can be in the range from about 1/100 toabout 6 pounds imidazolinone acid per acre, with dosages in the rangefrom about 0.03 to 0.5 pounds per acre being particularly preferred.More resistant plants or different field environments may require higherconcentrations and/or higher dosage rates, and a dosage rate may also beaffected by factors such as the use of other active herbicide compounds.The preparation of herbicide application compositions suitable to applyuseful dosages, based on the concentration of herbicide compound in asuspension concentrate or other concentrate comprising imidazolinoneacid, will be understood by one of ordinary skill.

[0120] Inventive herbicide compositions can be applied usingconventional aerial or ground spray techniques in field applications.The herbicide compositions can also be applied by any other usefultechnique, such as by spot-application to undesired plant growth using ahand-held applicator, or the like.

[0121] Vegetation that can be controlled using herbicide compositions ofthe invention generally include any type of vegetation that is or isknown to be controlled by imidazolinone or imidazolinone acid herbicidecompounds. The ingredients of the herbicide compositions, e.g.,surfactant, dispersant, acidifying agent, water, additional activeherbicide, etc., can be selected in view of the type of control desired(i.e. pre-emergent or post-emergent) and the type of vegetation to becontrolled according to the known attributes of imidazolinone compounds,including imidazolinone acid.

[0122] In one embodiment, a method of killing or controlling unwantedvegetation growth includes 1) preparing a herbicide composition thatincludes imidazolinone acid and an amount of acidifying agent other thansulfuric acid to reduce the pH of the herbicide composition to a pHbelow the pKa of the imidazolinone acid and 2) applying the herbicidecomposition to control plant growth.

[0123] In another embodiment, a method of killing or controllingunwanted vegetation growth includes 1) preparing a herbicide compositionthat includes suspension concentrate which includes imidazolinone acidand surfactant selected from the group consisting of a short chainalcohol ethoxylate nonionic surfactant, anionic surfactant, cationicsurfactant, and mixtures thereof, and 2) applying the herbicidecomposition to control plant growth. Optionally, such an embodiment mayinclude acidifying agent to reduce the pH of the herbicide compositionto below the pKa of the imidazolinone acid, the acidifying agentselected from the group consisting of sulfuric acid, hydrochloric acid,nitric acid, acetic acid, phosphoric acid, perchloric acid, andpolyphosphoric acid, and a sulfuric acid adduct of the formula:

[0124] wherein X is chalcogen, and each of R₁, R₂, and R₃ isindependently selected from hydrogen and organic radicals. In oneparticular embodiment acidifying agent is selected from the groupconsisting of phosphoric acid and an adduct of urea and sulfuric acid.

EXAMPLES Examples 1-3

[0125] Examples of suspension concentrates according to the inventioncan contain 4 lb. imidazolinone acid per gallon and can be prepared fromingredients including those described in Examples 1-3. In examples 1-3“AI” means “active ingredient.”

Example 1

[0126] Example 1 is an exemplary suspension concentrate that includes a4 lb. per gallon imidazolinone acid (imazethapyr acid), anionicsurfactant, anionic dispersant, thickener, and anti-microbial agent.TABLE 1 Example 1 Ingredients Ingredient % AI-Tech % Weight % AI Water44.90 SAG 30 Antifoam, 0.3 Witco Diethylene Glycol, 5.00 freezedepressant, Dow Morwet EFW 1.00 Wetter, Witco Imazethapyr Acid 98.040.80 39.98 Morwet D425, 3.00 dispersant, Witco 2% Kelzan - 0.5% 5.00Proxel Premix, thickener, Antimicrobial Total 100

Example 2

[0127] Example 2 is an exemplary suspension concentrate that includes a4 lb. per gallon imidazolinone acid (imazethapyr acid), acidifyingagent, anionic surfactant, anionic dispersant, and thickener. TABLE 1Example 2 Ingredients Ingredient % AI-Tech % Weight % AI Water 44.70 SAG30 Antifoam, 0.3 Witco Diethylene Glycol, 4.00 freeze depressant, DowUnite, Loveland 1.00 Industries, surfactant & acidifier, anionicImazethapyr Acid 98.0 42.00 41.16 Soprophor FLK, 2.50 Rhodia, Anionicdispersant 72% Phosphoric 0.50 Acid, acidifier Attaflow FL, 5.00Englehard, clay thickener Total — 100 —

Example 3

[0128] Example 3 is an exemplary suspension concentrate that includes a4 lb. per gallon imidazolinone acid (imazethapyr acid), nonionicsurfactant, nonionic dispersant, thickener, and anti-microbial agent.TABLE 3 Example 3 Ingredients Ingredient % AI-Tech % Weight % AI Water54.20 SAG 30 Antifoam, Witco 0.3 Propylene Glycol, freeze 5.00depressant, Dow Surfonic L12-6, wetting 1.00 agent, nonionic, HuntsmanImazethapyr Acid 98.0 31.00 30.38 Tersperse 4894, dispersant, 3.00nonionic, Huntsman 2% Kelzan - 0.5% Proxel 5.00 Premix, thickener,Antimicrobial Total — 100 —

Examples 4-5

[0129] The following examples illustrate how suspension concentrates ofthe invention can be used to control plant growth, optionally with anacidifying agent. PCC-1190 and PCC-1189 are examples of suspensionconcentrates having 3 pounds of active herbicide compound per gallon.

[0130] Materials and Methods:

[0131] Examples 4-5 represent experiments conducted to evaluate theefficacy of a variety of different types of herbicide formulations,including formulations from suspension concentrates, and to evaluate theeffect of adding acids to the spray solution as an acidifying agent (seeTables 4-6 for data from Example 4 and Tables 7 and 8 for data fromExample 5). Each treatment in the experiment was replicated three times.An untreated control was also included in the experiment.

[0132] Examples 4-5 were designed to determine the effect of adding fourdifferent acidifying agents (i.e., PCC-1174, LI-136, sulfuric acid, andphosphoric acid) to formulations of imidazolinone acid (PCC-1190 andPCC-1189) and the effect of applying each formulation at six differentrates (see data tables). These treatments were compared to PCC-1190 andPCC-1189 without the addition of an acidifying agent, a standardimidazolinone acid formulation (PURSUIT and SCEPTER), and an untreatedcontrol.

[0133] PCC-1189 Suspension Concentrate Formulation

[0134] PCC-1189 contains the active ingredient imazaquin acid.INGREDIENT % AI-Tech %/WT Water 54.20 SAG 30, OSI, Antifoam 0.30Proplyene Glycol, Antifreeze 5.00 Surfonic L12-6, Huntsman, nonionicwetting 1.00 agent Imazaquin Acid, Nat China, Active Ingredient 95.0031.00 Tersperse 4894, Huntsman, nonionic dispersant/ 3.50 wetterAttaflow FL 5.00 100.00

[0135] Add in order listed to cowles high speed mixer stopping prior toAttaflow FL thickener addition.

[0136] Grind to 5-18 microns, 4 hrs in attritor, 60%.

[0137] Let down to mix tank with scales

[0138] Add calculated amount of thickener (accounting for amount ofbatch that stays in the attritor) to milled liquid. Blend moderately for30 min.

[0139] PCC-1190 Suspension Concentrate Formulation

[0140] PCC-1190 contains the active ingredient imazethapyr acid.INGREDIENT % AI-Tech %/WT Water 54.20 SAG 30, OSI, Antifoam 0.30Proplyene Glycol, Antifreeze 5.00 Surfonic L12-6, Huntsman, nonionicwetting 1.00 agent Imazethapyr Acid, Nat China, Active Ingredient 98.0031.00 Tersperse 4894, Huntsman, nonionic dispersant/ 3.50 wetterAttaflow FL 5.00 100.00

[0141] Add in order listed to cowles high speed mixer stopping prior toAttaflow FL thickener addition.

[0142] Grind to 5-18 microns, 4 hrs in attritor, 60%.

[0143] Let down to mix tank with scales

[0144] Add calculated amount of thickener (accounting for amount ofbatch that stays in the attritor) to milled liquid. Blend moderately for30 min.

[0145] PURSUIT® is a commercially available product containing theactive ingredient imazethapyr acid. PURSUIT® is formulated as a 2SL(“2SL” means a “two pound per gallon soluble liquid”). SCEPTER® is acommercially available product containing the active ingredientimazaquin acid.

[0146] Acidifying Agents

[0147] Sulfuric Acid—0.9%

[0148] Phosphoric Acid—0.9%

[0149] PCC-1174 Acidifying Agent

[0150] Commercially available as “AMADS,” which is urea and H₂SO₄ inwater: Chemical Name 1-amino methanamide dihydrogen tetraoxosulfate, orsulfuric acid and urea Molecular Formula NH₂C(OH)NHSO₄H₂

INGREDIENT %/WT Water 22.99 93% Sulfuric Acid 48.65 99% Urea 26.64Stepfac 8170 1.71 SAG 10 Antifoam 0.01

[0151] LI-136 Acidifying Agent

[0152] LI-136 is a blend of 50 wt. % 21-0-0 urea liquor and 50 wtpercent of 72% phosphoric acid in water. The phrase “21-0-0 urea liquor”means a liquid that contains 21% by volume urea (nitrogen), 0% by volumephosphate (phosphorus), and 0% by volume potash (potassium).

[0153] Procedure

[0154] For the experiments, greenhouse flats 26 cm by 6 cm deep werefilled with Metro Mix 350 potting soil. The soil was pre-wetted beforefilling the flats. Six furrows were pressed into the soil in each flatusing a custom designed form. Corn, tame oats, velvet leaf (not used inExample 5), wheat, pinto beans, and sunflower were planted in each tray.One species was planted in each of the six rows in each flat. Five seedswere planted in each row of corn, pinto bean, and sunflower. Six seedswere planted in each row of tame oat and wheat. Because velvet leafseeds were so small, the seeds were sprinkled in each row and the numberof such seeds were not counted. Each flat was covered with 2 cm of MetroMix 350 potting soil and placed in the greenhouse. Greenhouse conditionswere 28/20 C day/night temperatures and 16/8 h day/night periods. Lightwas supplemented with 400 W sodium halide lights.

[0155] The plants were allowed to germinate and grow in the greenhousefor 2 weeks and then treated. Treatments were mixed using serialdilutions. Each dilution reduced the herbicide rate by one half. Allacidifying agents (e.g., PCC-1174, LI-136, sulfuric acid, and phosphoricacid) were calculated and mixed to provide acid concentrations of 0.9%.

[0156] After mixing, the pH of the spray solution of each treatment wasmeasured with a VWR Scientific model 8005 pH meter. The pH was measuredto determine if the acid used or the amount of acid added was sufficientto lower the pH below the pKa of the acid herbicides used.

[0157] At the time of treatment, crops were at the following stages:corn—2 to 3 lf, tame oat—2 to 3 lf, velvet leaf—2 lf (not used inExample 5), pinto bean—2-3 1 f, wheat—4 to 5 lf, and sunflower—2 lf.Plants were treated using a greenhouse track sprayer equipped with an8001E nozzle and calibrated to deliver 140 L ha-1 at the height of thecrop canopy. Each treatment was simultaneously applied to three trays ofplants, one for each replicate. After treatment, the plants were left inthe head house to dry and then transferred to the greenhouse. Plants ineach treatment were evaluated visually for injury 1 week and 2 weeksafter treatment. TABLE 4 Summary of Variables of Example 4 Volumes ofHerbicide Acid each Acid Rate Treatments (v/v %) Herbicide (lb AE/A)Plants Reps PCC-1174 2 PCC-1190 1 Corn, 3 Sulfuric 0.5 Tame oat,Phosphoric 0.25 Velvet leaf, LI-136 0.125 wheat 0.063 Pinto bean, 0.0313Sunflower

[0158] Following are data that illustrate the efficacy of variousherbicide compositions of Examples 4-5 and Summary of Variables ofExample 5. The injury caused by the herbicide treatment was ratedvisually. Plants were observed and compared to the untreated control.All the plants of each species in each replication were given a singlerating. A rating of 0=no injury—the plants look the same as theuntreated. A rating of 100=dead—usually highly necrotic, brown and nochance of producing seed.

[0159] Each of the acids was combined with the PCC-1190 or PCC-1189herbicide compositions to form a solution that contains 2 percent byvolume of a given 0.9% (of the acid) concentrated acidifying agent(e.g., PCC-1174, LI-136, sulfuric acid, and phosphoric acid), asindicated in Tables 4-8, and such that the pH of the herbicidecomposition was below the pKa of the particular herbicide compound.

[0160] The ingredients of the herbicide compositions as applied arelisted in the following tables, and were diluted with water and used atthe rates indicated for herbicide ingredients and acidifying agents.TABLE 5 Data for Example 4 (One Week) Velvet Pinto Herbicide Rate UnitsCorn Tame Oat Leaf Wheat Bean Sunflower 1 PURSUIT .0313 LB AE/A 0.0 10.050.0 10.0 10.0 50.0 2 PURSUIT 0.063 LB AE/A 0.0 20.0 50.0 20.0 10.0 50.03 PURSUIT 0.125 LB AE/A 0.0 30.0 50.0 20.0 20.0 50.0 4 PURSUIT 0.25 LBAE/A 0.0 50.0 50.0 20.0 30.0 70.0 5 PURSUIT 0.5 LB AE/A 0.0 60.0 50.030.0 40.0 90.0 6 PURSUIT 1 LB AE/A 10.0 60.0 50.0 50.0 40.0 98.0 7PCC-1190 .0313 LB AE/A 0.0 10.0 50.0 10.0 10.0 50.0 8 PCC-1190 0.063 LBAE/A 0.0 20.0 50.0 20.0 20.0 50.0 9 PCC-1190 0.125 LB AE/A 0.0 30.0 50.020.0 20.0 60.0 10 PCC-1190 0.25 LB AE/A 0.0 50.0 50.0 30.0 40.0 70.0 11PCC-1190 0.5 LB AE/A 0.0 60.0 50.0 40.0 40.0 90.0 12 PCC-1190 1 LB AE/A0.0 60.0 50.0 50.0 60.0 98.0 13 PCC-1190 .0313 LB AE/A 0.0 20.0 50.010.0 10.0 50.0 PCC-1174 2 % V/V 14 PCC-1190 0.063 LB AE/A 0.0 20.0 50.010.0 10.0 50.0 PCC-1174 2 % V/V 15 PCC-1190 .0125 LB AE/A 0.0 30.0 50.020.0 20.0 70.0 PCC-1174 2 % V/V 16 PCC-1190 0.25 LB AE/A 0.0 50.0 50.020.0 30.0 80.0 PCC-1174 2 % V/V 17 PCC-1190 0.5 LB AE/A 0.0 60.0 50.030.0 40.0 98.0 PCC-1174 2 % V/V 18 PCC-1190 1 LB AE/A 0.0 60.0 50.0 50.050.0 98.0 PCC-1174 2 % V/V 19 PCC-1190 .0313 LB AE/A 0.0 10.0 50.0 10.010.0 40.0 SULFURIC ACID 2 % V/V 20 PCC-1190 0.063 LB AE/A 0.0 20.0 50.020.0 20.0 50.0 SULFURIC ACID 2 % V/V 21 PCC-1190 .0125 LB AE/A 0.0 30.050.0 20.0 30.0 50.0 SULFURIC ACID 2 % V/V 22 PCC-1190 0.25 LB AE/A 0.040.0 50.0 30.0 50.0 80.0 SULFURIC ACID 2 % V/V 23 PCC-1190 0.5 LB AE/A0.0 50.0 60.0 50.0 50.0 90.0 SULFURIC ACID 2 % V/V 24 PCC-1190 1 LB AE/A0.0 60.0 60.0 50.0 60.0 98.0 SULFURIC ACID 2 % V/V 25 PCC-1190 .0313 LBAE/A 0.0 10.0 50.0 10.0 10.0 50.0 PHOSPHORIC 2 % V/V ACID 26 PCC-11900.063 LB AE/A 0.0 20.0 50.0 10.0 10.0 50.0 PHOSPHORIC 2 % V/V ACID 27PCC-1190 .0125 LB AE/A 0.0 20.0 50.0 10.0 20.0 50.0 PHOSPHORIC 2 % V/VACID 28 PCC-1190 0.25 LB AE/A 0.0 30.0 50.0 30.0 30.0 50.0 PHOSPHORIC 2% V/V ACID 29 PCC-1190 0.5 LB AE/A 0.0 40.0 50.0 40.0 40.0 70.0PHOSPHORIC 2 % V/V ACID 30 PCC-1190 1 LB AE/A 0.0 40.0 50.0 50.0 50.090.0 PHOSPHORIC 2 % V/V ACID 31 PCC-1190 .0313 LB AE/A 0.0 10.0 50.010.0 10.0 50.0 LI 136 2 % V/V 32 PCC-1190 0.063 LB AE/A 0.0 10.0 50.010.0 10.0 50.0 LI 136 2 % V/V 33 PCC-1190 .0125 LB AE/A 0.0 20.0 50.020.0 20.0 50.0 LI 136 2 % V/V 34 PCC-1190 0.25 LB AE/A 0.0 40.0 50.020.0 30.0 70.0 LI 136 2 % V/V 35 PCC-1190 0.5 LB AE/A 0.0 40.0 50.0 30.030.0 70.0 LI 136 2 % V/V 36 PCC-1190 1 LB AE/A 0.0 50.0 50.0 40.0 40.095.0 LI 136 2 % V/V 37 UNTREATED 0.0 0.0 0.0 0.0 0.0 0.0

[0161] TABLE 6 Data for Example 4 (Two Week) Tame Velvet Pinto HerbicideRate Units Corn Oat Leaf Wheat Bean Sunflower 1 PURSUIT .0313 LB AE/A20.0 20.0 50.0 20.0 30.0 50.0 2 PURSUIT 0.063 LB AE/A 20.0 20.0 50.020.0 30.0 50.0 3 PURSUIT 0.125 LB AE/A 20.0 40.0 50.0 30.0 35.0 50.0 4PURSUIT 0.25 LB AE/A 20.0 50.0 60.0 40.0 35.0 70.0 5 PURSUIT 0.5 LB AE/A20.0 70.0 60.0 70.0 45.0 95.0 6 PURSUIT 1 LB AE/A 20.0 80.0 70.0 75.055.0 100.0 7 PCC-1190 .0313 LB AE/A 10.0 20.0 50.0 20.0 25.0 50.0 8PCC-1190 0.063 LB AE/A 20.0 30.0 50.0 30.0 35.0 70.0 9 PCC-1190 0.125 LBAE/A 30.0 60.0 50.0 30.0 35.0 70.0 10 PCC-1190 0.25 LB AE/A 20.0 70.060.0 50.0 40.0 90.0 11 PCC-1190 0.5 LB AE/A 20.0 70.0 60.0 70.0 50.095.0 12 PCC-1190 1 LB AE/A 20.0 85.0 70.0 75.0 65.0 100.0 13 PCC-1190.0313 LB AE/A 10.0 50.0 50.0 25.0 30.0 70.0 PCC-1174 2 % V/V 14 PCC-11900.063 LB AE/A 10.0 50.0 50.0 40.0 30.0 80.0 PCC-1174 2 % V/V 15 PCC-1190.0125 LB AE/A 10.0 60.0 50.0 40.0 30.0 85.0 PCC-1174 2 % V/V 16 PCC-11900.25 LB AE/A 10.0 70.0 60.0 50.0 50.0 95.0 PCC-1174 2 % V/V 17 PCC-11900.5 LB AE/A 20.0 80.0 60.0 75.0 50.0 95.0 PCC-1174 2 % V/V 18 PCC-1190 1LB AE/A 20.0 90.0 70.0 85.0 70.0 100.0 PCC-1174 2 % V/V 19 PCC-1190.0313 LB AE/A 20.0 50.0 50.0 25.0 30.0 70.0 SULFURIC ACID 2 % V/V 20PCC-1190 0.063 LB AE/A 30.0 50.0 50.0 40.0 40.0 80.0 SULFURIC ACID 2 %V/V 21 PCC-1190 .0125 LB AE/A 23.3 60.0 50.0 40.0 35.0 85.0 SULFURICACID 2 % V/V 22 PCC-1190 0.25 LB AE/A 20.0 70.0 60.0 50.0 50.0 95.0SULFURIC ACID 2 % V/V 23 PCC-1190 0.5 LB AE/A 10.0 80.0 65.0 75.0 65.095.0 SULFURIC ACID 2 % V/V 24 PCC-1190 1 LB AE/A 20.0 95.0 70.0 85.080.0 100.0 SULFURIC ACID 2 % V/V 25 PCC-1190 .0313 LB AE/A 10.0 50.050.0 25.0 30.0 70.0 PHOSPHORIC 2 % V/V ACID 26 PCC-1190 0.063 LB AE/A20.0 50.0 50.0 40.0 30.0 80.0 PHOSPHORIC 2 % V/V ACID 27 PCC-1190 .0125LB AE/A 10.0 56.7 50.0 35.0 30.0 85.0 PHOSPHORIC 2 % V/V ACID 28PCC-1190 0.25 LB AE/A 20.0 66.7 60.0 50.0 40.0 95.0 PHOSPHORIC 2 % V/VACID 29 PCC-1190 0.5 LB AE/A 20.0 70.0 60.0 75.0 50.0 95.0 PHOSPHORIC 2% V/V ACID 30 PCC-1190 1 LB AE/A 20.0 76.7 70.0 75.0 70.0 100.0PHOSPHORIC 2 % V/V ACID 31 PCC-1190 .0313 LB AE/A 10.0 46.7 50.0 20.025.0 60.0 LI 136 2 % V/V 32 PCC-1190 0.063 LB AE/A 0.0 30.0 50.0 30.025.0 80.0 LI 136 2 % V/V 33 PCC-1190 .0125 LB AE/A 10.0 30.0 50.0 30.030.0 70.0 LI 136 2 % V/V 34 PCC-1190 0.25 LB AE/A 15.0 50.0 60.0 35.030.0 85.0 LI 136 2 % V/V 35 PCC-1190 0.5 LB AE/A 20.0 63.3 60.0 50.045.0 90.0 LI 136 2 % V/V 36 PCC-1190 1 LB AE/A 20.0 80.0 70.0 60.0 55.096.7 LI 136 2 % V/V 37 UNTREATED 0.0 0.0 0.0 0.0 0.0 0.0

[0162] TABLE 7 Summary of Variables of Example 5 Volumes of HerbicideAcid each Acid Rate (lb Treatments (v/v %) Herbicide AE/A) Plants RepsPCC-1174 2 PCC-1189 0.0155 Corn, 3 Sulfuric 0.031 Tame oat, Phosphoric0.0613 Wheat, LI-136 0.1225 0.245 Pinto bean, 0.49 Sunflower

[0163] TABLE 8 Data for Example 5 (Two Week) Tame Pinto Herbicide RateUnit Corn Oat Wheat Bean Sunflower 1 SCEPTER .0155 LB AE/A 0.0 0.0 0.00.0 0.0 2 SCEPTER 0.031 LB AE/A 0.0 0.0 10.0 20.0 30.0 3 SCEPTER .0613LB AE/A 0.0 0.0 0.0 10.0 10.0 4 SCEPTER .1225 LB AE/A 10.0 0.0 0.0 10.030.0 5 SCEPTER 0.245 LB AE/A 10.0 0.0 0.0 20.0 60.0 6 SCEPTER 0.49 LBAE/A 20.0 10.0 10.0 20.0 60.0 7 PCC-1189 .0155 LB AE/A 30.0 10.0 10.00.0 0.0 8 PCC-1189 0.031 LB AE/A 0.0 0.0 0.0 10.0 10.0 9 PCC-1189 .0613LB AE/A 20.0 10.0 0.0 10.0 10.0 10 PCC-1189 .1225 LB AE/A 20.0 10.0 10.010.0 60.0 11 PCC-1189 0.245 LB AE/A 40.0 20.0 10.0 20.0 60.0 12 PCC-11890.49 LB AE/A 30.0 10.0 10.0 10.0 70.0 13 PCC-1189 .0155 LB AE/A 30.020.0 10.0 10.0 20.0 13 PCC-1174 2 % V/V 14 PCC-1189 0.031 LB AE/A 10.020.0 10.0 20.0 70.0 14 PCC-1174 2 % V/V 15 PCC-1189 .0613 LB AE/A 30.030.0 20.0 30.0 60.0 15 PCC-1174 2 % V/V 16 PCC-1189 .1225 LB AE/A 40.030.0 20.0 30.0 70.0 16 PCC-1174 2 % V/V 17 PCC-1189 0.245 LB AE/A 50.030.0 20.0 40.0 60.0 17 PCC-1174 2 % V/V 18 PCC-1189 0.49 LB AE/A 50.010.0 10.0 60.0 90.0 18 PCC-1174 2 % V/V 19 PCC-1189 .0155 LB AE/A 10.00.0 0.0 10.0 30.0 19 SULFURIC ACID 2 % V/V 20 PCC-1189 0.031 LB AE/A20.0 0.0 0.0 10.0 30.0 20 SULFURIC ACID 2 % V/V 21 PCC-1189 .0613 LBAE/A 10.0 0.0 0.0 0.0 40.0 21 SULFURIC ACID 2 % V/V 22 PCC-1189 .1225 LBAE/A 10.0 0.0 0.0 10.0 40.0 22 SULFURIC ACID 2 % V/V 23 PCC-1189 0.245LB AE/A 20.0 0.0 0.0 20.0 60.0 23 SULFURIC ACID 2 % V/V 24 PCC-1189 0.49LB AE/A 20.0 10.0 10.0 30.0 80.0 24 SULFURIC ACID 2 % V/V 25 PCC-1189.0155 LB AE/A 10.0 0.0 0.0 10.0 50.0 25 PHOSPHORIC ACID 2 % V/V 26PCC-1189 0.031 LB AE/A 10.0 0.0 0.0 20.0 50.0 26 PHOSPHORIC ACID 2 % V/V27 PCC-1189 .0613 LB AE/A 15.0 0.0 0.0 30.0 40.0 27 PHOSPHORIC ACID 2 %V/V 28 PCC-1189 .1225 LB AE/A 10.0 0.0 0.0 25.0 50.0 28 PHOSPHORIC ACID2 % V/V 29 PCC-1189 0.245 LB AE/A 10.0 0.0 0.0 30.0 60.0 29 PHOSPHORICACID 2 % V/V 30 PCC-1189 0.49 LB AE/A 20.0 0.0 0.0 30.0 50.0 30PHOSPHORIC ACID 2 % V/V 31 PCC-1189 .0155 LB AE/A 20.0 0.0 0.0 10.0 20.031 LI136 2 % V/V 32 PCC-1189 0.031 LB AE/A 20.0 0.0 0.0 10.0 10.0 32LI136 2 % V/V 33 PCC-1189 .0613 LB AE/A 10.0 0.0 0.0 10.0 30.0 33 LI1362 % V/V 34 PCC-1189 .1225 LB AE/A 30.0 20.0 20.0 30.0 20.0 34 LI136 2 %V/V 35 PCC-1189 0.245 LB AE/A 30.0 10.0 10.0 30.0 40.0 35 LI136 2 % V/V36 PCC-1189 0.49 LB AE/A 10.0 0.0 0.0 20.0 70.0 36 LI136 2 % V/V 37Untreated 0.0 0.0 0.0 0.0 0.0

We claim:
 1. A herbicide composition comprising a suspension concentratecomprising an imidazolinone acid, and acidifying agent other thansulfuric acid in an amount so the pH of the composition is below the pKaof the imidazolinone acid.